Logs the user out of a website and prevents the onlogin action from automatically firing on their next visit.

Users with third-party cookies disabled may experience problems logging in using the Observer API as detailed in issue 2999.

The "Callback" API (Current)

The Callback API was introduced in November 2011. It improved upon the initial API by allowing options to be passed to navigator.id.get() and offering experimental support for BrowserID-managed persistent sessions.